In the field of metal working, a process of cutting a long sheet body into workpieces each in a desired size and stacking these workpieces to make a so-called stack is performed.
Then, these workpieces in a stack state are conveyed to a predetermined metal working machine, are taken from the stack one by one, and are subjected to metal working such as press working.
Meanwhile, in the process of stacking workpieces to make a stack, it is desired to quickly and accurately stack workpieces without damage.
For example, as a workpiece loading method, a method using a magnet-attraction-type conveyor has been known in which magnetic sheet bodies made of a magnetic material supplied from a device of the previous process are sequentially conveyed above a multilayered part as being attracted to a belt by a plurality of electromagnetic magnets and dropped onto the multilayered part (for example, refer to PTL 1).
Also, a metal sheet conveying method has been known in which metal sheets obtained by cutting by a blanking press are conveyed by a runout conveyor, are transferred by being magnetically attracted to a magnetically-attracting belt of a piler conveyor with a plurality of electromagnetic magnets continuously disposed, and then are conveyed by a piler conveyer and dropped by causing the magnetic force of the electromagnetic magnets to be lost at a piling position straight above a loading part to be sequentially loaded on the loading part (for example, refer to PTL 2).